Fuse-plug



FUSE PLUG.

APPLICATION FiLED JAN. 17, 19H. 1,339,499. Patented Feb. 10,1920.

zzz.;

in I7 l J5 J3 i 4 J7 i J 3 J2 4 f4 J4 9 z I .4 C 6 SIDNEY T. SJOBERG,OIF MINNEAPOLIS, MINNESOTA.

FUSE-PLUG.

Specification of Letters Patent.

Patented Feb. 10, 1920.

Application filed January 1'7, 1917. Serial No. 142,810.

To all who/1L t may concern:

Be it known that I, SIDNEY T. SJOBERG,

la citizen of the United States, resident of Minneapolis, county ofHennepin, State of Minnesota, have invented certain new and usefulImprovements in Fuse-Plugs, of which the following is a specification.

My invention relates to multiple fuse plugs'andthe Vobject of theinvention is to improve the type .of plug shown and described in mypending application for Letters Patent of the United States, Serial No.79,488, filed February 21, 1 916.

A further object is t0 provide a multiple fuse plug of extremely simpleconstruction and one which can be manufacturedat a low cost.

The invention consists generally in various constructions andcombinations, all aS hereinafter described and particularly pointed outin the claims.

In the accompanying drawings forming part of this specifica-tion,l

Figure 1 is a longitudinal sectional view through a fuse plug embodyingmy invention,

Fig. 2 is an outside view with the wall of the fuse plug broken away,

Fig. 3 is a horizontal sectional view on the line3-3 of Fig. 1,

Fi 4 is a similar view on ofFig. 1,

Fig. 5 is a plan View, showing the means for indicating when a certainfuse has burned out, y

Fig. 6 is a sectional view on the line 6 6 of Fig. 1,

Fig. 7 is a sectional view of the top of the fuse plug, showing a burnedout -fuse and an indicating means therefor in the cap of the plug.

In the drawing, 2 represents one member of the plug and 3 anothermember, both composed of insulating material, preferably porcelain.These members have a central orifice 4 extending therethrough to receivea Contact pin 5, the members revolving on the pin to shift the circuitfrom one fuse Wire to another. This pin. has at its inner end a head 6forming a contact surface and an insulating washer 7 is interposedbetween this head and the shell contact 8 to prevent possibility ofarcing at this point, said shell Contact ybeing threaded to receive theend of the insulating member 2, as yusual in plugs of this type, and atongue 9, of

the line 4 4 suitable conducting material forming a spring contact, ismounted at one end on the shell contact 8 and projects upwardly througha hole l0 in the flanged upper end of the member 2 and into a recess 11that is formed in the lower end of the plug member 3, the walls ofsaidrecess depending and encircling the upper end of the tongue orspring conta-ct. The member 3 is provided with a plurality of holes orsockets 12 therein, extending through the same from end to end' andcommunica-ting at one end with the recess 11 and there may be anydesired number of these holes according to the number of fuse wires tobe used.

13 represents the fuse wires, each having a cap 14 at one end,preferably concave in form, tting into the inner end of a socket 12adjacent to the recess 11, the fuse wires extending centrally throughthe sockets and having their opposite ends soldered ,to radially7projecting lugs 15 vformed on a. head 16 of the pin 5 and seated withina recess 17 in the end of the member 3.l The lugs 15 seated in sockets1'6 in the end of the member 3 prevent the pin 5 from \lturningindependently of the member 3 and breaking the fuse connections betweenthem. These two parts of the plug must turn together in the operation ofshifting the contact from one fuse wire to another.

`Between the sockets 18 the member 3 is provided with insulatingpartitions 19 separating the socket of one fuse wire from all the othersand forming a series of independent lchambers 20 in the en dof themember 3. A metallic cap 21 is fitted over the end of the member 3 inany preferred manner. A disk 22 of mica, or similar material, isinterposed between the cap 21 and the top of the partitions 19, and thecap 21 has a series of openings 23 therein through which and the sheetof mica the fuse wire sockets may be visible. sheet of mica or othertransparent material will be discolored where its surface is exposed tothe smoke of the fuse wire in the chamber to indicate that the fuse orconnection in that chamber has burned out.

In 7 a modification is shown, in which a disk 24 of suitable materialhas holes 25 therein in which wafer-like members 26 of a suitablefusible material are inserted. lVhen a fuse wire burns out, the heatwill melt the wafer and indicate the exact position of the burned outfuse.

The under surface of the4 position of the Contact spring and the memberof the fuse by the markings on the outer surface of the plug.

An essential characteristic of a fuse plug of this type is aconstruction in which there will be no danger of arcin'of and at thesame time an article of -this k1ndto be salable must be capable ofeconomical manufacture. Unless the plug is of the character described,it cannot enter into extensive use or successfully pass the underwriterstests.

I claim as my invention:

1.Y A multiple'fuse plug comprising a contact pin, insulating membersmounted for relative rotation thereon, a head` secured to said in, fusewires connected to one end or' said ead and having contact surfaces inone of said' members, a shell contact mounted on the other member andhaving means for engaging the contact surfaces of said fuse wiressuccessively said members are relatively rotated, a cap for concealingone end of one of said members and having openings therein correspondingin number to the number of said fuse wires, and partitions radiatingfrom said pin adjacenty to the point of connection with' said fuse wiresand dividing the spaces between said fusev `fuse' wire being indicatedon the part oi? said'diskl closing the opening leading to the chamber inl which the burned fuse is mounted.

2. A multiple'fuse plug comprising a contact pin, insulating membersmounted thereon for relative rotation, o ne of said members having aseries of iz'use wires mounted at intervals therein and provided withcontact surfaces, the other member havin a head at its inner end lorcontact with said nrst member and provided with'a smaller outer end, ashell contact fitting saidV smaller outer end and having a tongue memberprojecting through said head forv engagement with said contactingsurfaces successively when said members are revolved, andan indicatingdevice formed on said head and bridging the joint between it and vtheother insulating member opposite and adjacent the contacting surfacesof' said tongue member and forming an exterior indicator to determinethe position of said vtongue member with respect to said contactsurfaces.

In witness whereof,4 I' have hereunto set my hand this 12 day ofJanuary, 1917.

SIDNEY T. sJoBERG. I

